In the related art, as a torque sensor that detects a torque in the rotation direction, there is a known torque sensor in which a strain sensor for measuring a strain in a strain body that deforms due to rotation is attached to the strain body (for example, see PTL 1). In a joint of a robot on which loads in various directions act, in order to accurately detect a torque in the rotation direction acting on the joint, a strain cancellation mechanism is constituted of a bridge circuit that uses many strain sensors, to exclude loads in directions other than the rotation direction.